Help Identifying Brass 'things'

Cleaning out the garage today, I found a bunch of 'things' that I had forgotten about. They came with several old LF and ULF cameras I had purchased.

They are all brass sheets, and all have ovals cut out of them. The exterior dimensions run from 6x8 to nearly 5x7 to 4x5 and on and on. Some are purely rectangular in shape, some have the edges clipped.

I'm guessing that these are vignette shapes for printing but thought I should ask since I've often been wrong before. Does anyone actually know what these would be for and how they are used?

Thanks,
Richard

They could also be vignettes for the camera. I've seen sets for sale on ebay that were to be used on the compendium/filter holder of mf and lf cameras. Some for forming a portrait oval when shooting. Others for blacking out one side of the neg for double exposures. Some in a straight vertical line and others at an angle. Some a straight cut and others with a saw tooth pattern on the edges.

Based on the items they came with (old LF and ULF cameras), my guess would also be for in-camera vignetting or multi-image masking.